1. Field of the Invention
The present invention relates to a tamper indicating tape made from a film capable of splitting internally for use with a package to indicate opening of the package.
2. Discussion of the Art
In grocery stores, packages, e.g., boxes, cans, bags, are subject to entry by various classes of tamperers. One type of tamperer primarily opens the package, consumes all or a portion of the contents, reseals the package, and then places the resealed package back on the shelf. Another type of tamperer primarily opens the package, introduces a foreign object therein, e.g., poison, reseals the package, and then places the resealed package back on the shelf. In the first situation, there is little possibility of physical harm to the consumer, so the store manager can merely discard the tampered package. In the second situation, a rumor involving introduction of foreign objects can lead to an expensive recall of all of the products packaged in packages identical to the tampered package.
U.S. Pat. No. 4,652,473 discloses a pressure-sensitive adhesive tape comprising a backing having two separate layers that delaminate. The outer layer has sufficiently high tensile strength to maintain its integrity when removed from the tape and the inner layer adjacent the adhesive is thin and deformable, so that the outer layer cannot be removed from the inner layer without disrupting the adhesive bond of the inner layer to the pressure-sensitive adhesive, thereby providing tamper indication.
U.S. Pat. No. 4,630,891 discloses a tamper resistant security film comprising a monolayer of transparent microspheres supported in a thin layer of binder material. A layer of pressure-sensitive adhesive is coated onto the binder material and at least one patterned layer having differential adhesion to the pressure-sensitive adhesive layer and the binder layer such that upon attempted removal of the film from a substrate at elevated temperature, the film splits, with part of the film remaining on the substrate and part being removed, thereby providing tamper indication.
U.S. Pat. No. 4,557,505 discloses a stress-opacifying tamper indicating tape for use on closures. The tape comprises a stress opacifying translucent polymeric backing having an exposed surface on which is printed indicium by the use of a colored ink material which is preferably translucent and on the opposite surface of the backing is indicium of a contrasting color which opposite surface is also flood coated and colored in the background areas of the contrasting color indicium with a color substantially similar to that of said printed indicium on the exposed surface. The stress opacifying backing will become opaque when subjected to stress and produce a color which will enhance the printed indicium and obliterate the contrasting color indicium.
None of the tapes in the foregoing references are effective against both the consuming tamperer and the adulterating tamperer.